Find a way to support custom Math expressions

Sample output of the english Wiktionary parsing:

<math> ERROR with \begin{align}\frac{\pi}{2} & = \prod_{n=1}^{\infty} \frac{ 4n^2 }{ 4n^2 - 1 } = \prod_{n=1}^{\infty} \left(\frac{2n}{2n-1} \cdot \frac{2n}{2n+1}\right) \\[6pt]& = \Big(\frac{2}{1} \cdot \frac{2}{3}\Big) \cdot \Big(\frac{4}{3} \cdot \frac{4}{5}\Big) \cdot \Big(\frac{6}{5} \cdot \frac{6}{7}\Big) \cdot \Big(\frac{8}{7} \cdot \frac{8}{9}\Big) \cdot \; \cdots \\\end{align} in [Wallis product]

<math> ERROR with f:\Z_2^n \to \Z_2 in [bent function]

<math> ERROR with \frac = \frac in [circle of Apollonius]

<math> ERROR with \and in [conjunction]

<math> ERROR with n\in\N in [elementary symmetric polynomial]

<math> ERROR with (x_1, x_2, \ldots, x_m, y)\in\R^{m+1} in [graph]

<math> ERROR with f: \R^m\rightarrow\R in [graph]

<math> ERROR with a_i \isin R in [group ring]

<math> ERROR with \R^3 in [halfway model]

<math> ERROR with \begin{align}\rho(g, h) (0,x_1,\ldots,x_k) &= g(x_1,\ldots,x_k) \\\rho(g, h) (y+1,x_1,\ldots,x_k) &= h(y,\rho(g, h) (y,x_1,\ldots,x_k),x_1,\ldots,x_k)\,\end{align} in [primitive recursion]

<math> ERROR with \isin in [supermodular]

I guess Mediawiki is using custom symbols somehow. We should find a way to handle them.

[lasconic]

I found why the few words using \begin{align} don’t work.

See https://comp.text.tex.narkive.com/zTTDqtBD/help-with-amsmath-align-not-possible

render_expr = f"{expr}" if expr.startswith("\\begin{align}") else f"${expr}$"

would fix it but we need to change the IMAGE_CSS… Needs more work.

[lasconic]

Note for later, to debug latex output, add "-d -1" in dvioptions